Source: SOLMEM LLC submitted to NRP
A LOW COST SOLAR DESALINATION METHOD FOR AGRICULTURE DRAINAGE MANAGEMENT
Sponsoring Institution
National Institute of Food and Agriculture
Project Status
COMPLETE
Funding Source
SMALL BUSINESS GRANT
Reporting Frequency
Annual
Accession No.
1022922
Grant No.
2020-33610-31578
Cumulative Award Amt.
$99,992.00
Proposal No.
2020-00883
Multistate No.
(N/A)
Project Start Date
Sep 1, 2020
Project End Date
Jun 30, 2021
Grant Year
2020
Program Code
[8.4]- Air, Water and Soils
Recipient Organization
SOLMEM LLC
101 PARKLAND BLVD STE 103
SUGAR LAND,TX 774785521
Performing Department
(N/A)
Non Technical Summary
Agriculture drainage water management faces great challenges in semi-arid regions with significant irrigated agriculture. Drainage management strategies such as cost-efficient treatment and reuse of drainage water for irrigation are needed to control salinity accumulation in irrigation water and soil, to minimize contamination of natural surface water and potential harm to wildlife, and to alleviate local and regional water stress. We propose to develop a low cost solar desalination method to treat agriculture drainage water for irrigation. The technology will be developed based on the Nanophotonic Enhanced Solar Membrane Distillation (NESMD) process invented at Rice University. Building upon several ongoing research activities, the proposed Phase I study will assess the technical and economic feasibility of using the NESMD process for high TDS agriculture drainage water treatment and reuse. Specifically, we will (1) investigate the impact of water quality of agricultural drainage on system performance, (2) investigate the impact of environmental parameters and the mode of operation, (3) evaluate optimal operating conditions, (4) conduct preliminary cost estimation and pilot NESMD system design. The proposed Phase I study will provide the necessary performance and cost data specific to agriculture water applications. It will allow us to identify any remaining technical barriers, and prepare us for field study and demonstration in Phase II
Animal Health Component
40%
Research Effort Categories
Basic
50%
Applied
40%
Developmental
10%
Classification

Knowledge Area (KA)Subject of Investigation (SOI)Field of Science (FOS)Percent
11102102020100%
Knowledge Area
111 - Conservation and Efficient Use of Water;

Subject Of Investigation
0210 - Water resources;

Field Of Science
2020 - Engineering;
Goals / Objectives
The over archinggoal of the project is to develop a low-cost, efficient desalination system based on the NESMD technology to treat agriculture drainage for irrigation reuse. Through the proposed Phase I research, we expect to achieve the following objectives:1) assessing the commercialization potential of the NESMD technology specifically for agriculture drainage treatment; 2) completing the bench-scale research and reactor/system design necessary for a pilot study in Phase II.
Project Methods
The project will perform bench-scale experiments to determine the impact of agriculture drainage water quality (e.g., salinity, turbidity, organic contents), enviornmental conditions (e.g., solar irradiance, ambient temperature and humidity), and operating conditions (e.g., feedcrossflow velocity, MD operation mode, heat recovery method)on three key system performance perameters: membrane flux, water recovery, and TDS removal.These performance parameters will then be used to perform a preliminary cost analysis to determine the cost of irrigation drainage water treatment and reuse at specific geographic locations. We will follow DOE's definition of "levelized cost of water" (LCOW) for our cost analysis, and use NASA solar irradiance and temperature database for environmental conditions.Efforts: The knowledge generated by the project will be disseminated in several ways:1) A presentation at the SBIR/STTR Spring Conference2) A module on solar desalination technologies in Prof. Qilin Li's graduate level course CEVE 535 Physical and Chemical Processes for Water Quality Control3) A seminar at the Nanosystems Engineering Research Center for Nanotechnology Enabled Water Treatment (NEWT).4) Hands on training of a graduate student to perform NESMD experiment5) Communications with stakeholders (farmers, water authorities, USDA field offices)Our efforts will be evaluated through the following ways:1) Research effort will be evaluated by the completeness, and robustness of the study as measured by the quantity and quality of bench-scale experimental data collected;2) Potential of the technology will be evaluated using the performance data collected during the project as well as the preliminary cost. The performance and cost will be compared with benchmark technologies that are commercially available now, e.g., ultrahigh pressure RO and mechanical vapor compression.3) Our education and outreach effort will be measured using 1) presentation evaluation forms that will be distributed at the conference and the NEWT seminar; 2) class evaluation results at Rice University; and 3) outcome of the graduate student's semi-annual review implemented at Rice University.

Progress 09/01/20 to 06/30/21

Outputs
Target Audience:The target audience for this report is anyone involved with water treatment, agriculture, irrigation, & the resulting contaminated agricultural drainage water and the agirculutre drainge evaporation ponds. The purpose of this report is to provide a technical and economic analysis of a novel solar desalination method that can: 1. treat agriculture drainage to potable water standards to mitigate the negative environmental impact of agriculture drainage water 2. treat the concentrated agrilcuture drainge water in evaporation ponds to reclaim the extensive amount of land used for evaporation ponds and mitigate the negative environmental impacts of evaporation ponds. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?SolMem provided opportunities for professional development to undergraduates, graduates, and research professionals. An undergraduate student helped conduct research which was used as the foundation for the technoeconomic report; helearnedmembrane distillation fundamentals,key technoecomic performance parameters of NESMD (GOR, flux, LCOW), and how to work as part of a team. A Rice graduate student helped develop the experimental apparatus and helped with the water quality analysis, gaining hands on experience. A research professional conducted the experiments, analyzed the results, and generated the report, gaining experience on conducting stuctured research under a government grant. How have the results been disseminated to communities of interest?SolMem is using its connections in the water treatment field to disseminate the results of this grant, which indicate that our technology is a cost effective solution for managing agriculture drainage water. Specifically, SolMem is currently engaged with BlueTechValley, a California based organization whose members are academic and professional experts in water treatment and agriculture; we will use our connections with this organization to find potential demonstration sites for our pilot plant. Any connections that the USDA can provide in the agriculture drainage segment would be greatly appreciated. What do you plan to do during the next reporting period to accomplish the goals? Nothing Reported

Impacts
What was accomplished under these goals? USDA SBIR Phase 1 Grant Final Report: Abridged 1 Introduction A Low Cost Desalination Method for Agriculture Drainage Management investigates a novel membrane distillation (MD) method called nano photonic enabled membrane distillation (NESMD) to produce pure water from agriculture drainage water using sunlight as the only energy source. 2 Experimental Results & Discussion 2.1 Impact of Solar Intensity on NESMD Performance NESMD experiments were conducted under 500, 1000, 1500, 2000, and 5000 W/m2. Key performance indicators (KPI) were flux, GOR (an efficiency parameter that represents the ratio energy consumed to treat feedwater to the energy delivered to NESMD membrane), and water recovery. All three KPIs substantially increased as solar intensity increased. Under 5000 W/m2 a flux of ~5 LMH, a GOR of 63%, and a water recovery of 99% were achieved. SolMem recommends coupling the NESMD technology with a parabolic trough to deliver concentrated sunlight to enable MLD. 2.2 Impact of Salinity on NESMD Performance Experimental results indicate that feed salinity does not adversely impact NESMD performance until around ~70,000 ppm. Agriculture drainage water ranges from hundreds of ppm up to a hundred thousand ppm. These results indicate that NESMD is suitable to treat agriculture drainage water up to ~70,000 ppm with 1000 W/m2 of solar irradiation. 2.3 Impact of Feed Flow Rate on NESMD Performance Results indicated that feed flow rate does not adversely impact NESMD flux or GOR, but adversely impacts the water recovery. It is recommended to use the lowest feed flow that maximizes water recovery, but does not induce membrane scaling from increased concentration of the feed solutes. 2.4 Impact of Coolant Flow Rate on NESMD Performance Results indicated that coolant flow rate does not have a large impact on NESMD performance at the lab scale. NESMD performance is not impacted as long as the coolant flow rate has sufficient capacity to receive the latent heat of condensation of the product vapor. Future experiments should investigate extremely low and extremely high coolant flow rates to further validate the above claim. Additionally, experiments need to be conducted at a bench/pilot scale, as heat and mass transfer behave differently at a larger scale. 2.5 Removal of As, Se, B Arsenic, selenium, and boron are troublesome contaminants commonly found in agriculture drainage water. ICP-OES and conductivity meter results confirmed that membrane distillation treated 100% of arsenic, selenium, and boron from the simulated agriculture drainage evaporation pond water. Complete removal arsenic and selenium indicates that NESMD is a robust and reliable treatment method for the most extreme case of agriculture drainage water. 2.6 Impact of TOC on NESMD Performance Organic compounds are commonly found in agriculture drainage water, and the concentration of organics is typically measured in ppm of total organic carbon (TOC). Experiments were performed at the highest concentrations of organics found in agriculture drainage literature (93 ppm) to exhibit a worst-case scenario, under 1000 W/m2. Flux results indicated that organic fouling does not have a significant impact on NESMD performance over the course of a single day of operation. 2.7 Impact of scaling ions (Ca, Mg, SO4, CO3) on NESMD performance Agriculture drainage water contains common scaling compounds, such as calcium/magnesium -carbonates/sulfates; Flux results indicate the NESMD is adversely impacted by the presence of common scaling compounds. While no wetting events occurred (transport of feed solute to the product freshwater), the flux clearly decreased as the day of NESMD operation progressed. It is recommended that antiscalant is added to the NESMD feed in order to mitigate the adverse impacts of scaling compounds on flux, and to prevent wetting events. 3 Pilot Plant Analysis Experimental results indicate that NESMD has the potential to treat feedwater up to 250,000 ppm TDS to generate freshwater well within EPA drinking water standards and operate at minimum liquid discharge (MLD). SolMem believes these results merit a pilot scale analysis of NESMD. 3.1 Pilot Plant Pre-treatment Requirements First hand analysis and research of agriculture drainage water revealed that the pilot plant will require the following pre-treatment operations: cartridge filter, and chemical dosing pumps for addition of antiscalant and sodium hypochlorite. 3.2 Pilot Plant Cleaning in Place (CIP) System Research into common membrane distillation system revealed that oxalic & citric acid is required for acidic cleaning of scaling, sodium hydroxide is required for caustic treatment of organic fouling, and an air compressor/blower will be needed to dry membranes if a wetting events occurs. 4 Technoeconomic Analysis The first competitive area for NESMD is off-grid desalination of agrilculture drainage water. The primary competing technology in the off-grid desalination area is photovoltaic panels coupled with RO desalination (PV-RO). The main advantage of PV-RO is the use of renewable solar energy and the availability of commercial parts. The main disadvantages include the low energy efficiency of PV panels, high energy costs of RO, and feedwater limitations of RO. PV-RO systems have a TDS operational range of 0 - 70,000 ppm. Existing PV-RO plants have reported LCOW over a wide range 2.3 - 13 $/m3. The LCOW for PV-RO is a strong function of location. The second competitive area for NESMD is the concentration of brines beyond the operational limit of RO (TDS >70,000 ppm). NESMD's main competing technology in the field of brine concentration are mechanical vapor compression (MVC) brine concentrators (BC). Quotes from brine concentrator vendors have an average LCOW range of 7.5 - 29 $/m3. The model for a single effect NESMD unit has a predicted LCOW range of 1.6 - 8 $/m3. If SolMem develops multi-effect NESMD technology, the predicted LCOW range is 1.10 - 2.5 $/m3. 4.2 Sensitivity Analysis & Cost Minimization Strategy There are four main cost components to the NESMD LCOW: 1. System equipment capital cost 2. Parabolic trough capital cost 3. System equipment operational cost 4. Parabolic trough operational cost. The sensitivity analysis of SolMem's LCOW model revealed that NESMD LCOW is the strongest function of GOR, system equipment cost, and parabolic trough cost. By maximizing the GOR through a multi-effect NESMD reactor, minimizing the parabolic trough cost through strategic partnerships with companies developing state-of-the-art parabolic troughs, and predicting the impact of feed salinity on the LCOW, SolMem can offer a competitive, low solar powered desalination that offers a simple solution to complex wastewater problems, capable of achieving minimum liquid discharge in a single unit operation.

Publications